One of the major challenges of motor control is understanding how the central nervous system controls the degrees of freedom of the human body. Postural control of the trunk is essential for all other motor tasks. This foundational motor task is typically accomplished by 9 to 10 months of age when infants are able to sit independently. From that age on the spine is so well controlled that it is acceptable in posture control research to consider the trunk as one segment. Surprisingly little is known about how infants learn to control multiple segments of the spine. In this proposal, a novel approach allows evaluation of limited segments of the spine allowing measurement of upright postural control prior to the development of independent sitting. I will evaluate development of spinal control in a longitudinal study of infants from 3 months to 9 months of age and compare EMG and kinematic data from this group with data obtained from children with cerebral palsy who have been unable to achieve independent sitting balance. This knowledge will allow clinicians to develop new methods of training and evaluation and new types of supportive devices. The technique will also enhance the potential for research on development of motor control of the trunk. [unreadable] [unreadable] [unreadable]